Zoom lens and image pickup apparatus

Abstract

The zoom lens includes in order from an object side to an image side where N represents an integer equal to or more than 5, a first lens unit, a second lens unit, an (N−2)-th lens unit, an (N−1)-th lens unit and an N-th lens unit respectively having positive, negative, positive, negative and positive refractive powers. The (N−1)-th lens unit includes an image stabilizing lens unit. The conditions of 0.01<BldN/TDw<0.09 and 2.0<f N /fw<8.0 are satisfied where BldN represents a length of the N-th lens unit on the optical axis, TDw represents a distance on the optical axis between a most object side lens surface and a most-image side lens surface at a wide-angle end, fw represents a focal length of the entire zoom lens at the wide-angle end, and f N represents a focal length of the N-th lens unit.

What is claimed is:  
     
       1. A zoom lens comprising in order from an object side to an image side where N represents an integer equal to 5 or 7:
 a first lens unit having a positive refractive power; 
 a second lens unit having a negative refractive power; 
 an (N−2)-th lens unit having a positive refractive power; 
 an (N−1)-th lens unit having a negative refractive power; and 
 an N-th lens unit having a positive refractive power, 
 wherein distances between adjacent ones of the first, second, (N−2)-th, (N−1)-th and N-th lens units in a direction of an optical axis are changed during zooming, 
 wherein the (N−1)-th lens unit includes an image stabilizing unit movable for image blur correction in a direction including a directional component orthogonal to the optical axis, and 
 wherein the following conditions are satisfied:
   0.01 <BldN/TDw< 0.09 
   2.0 <f   N   /fw< 8.0 
 
 where BldN represents a thickness of the N-th lens unit on the optical axis, TDw represents a distance on the optical axis between a most object side lens surface and a most-image side lens surface at a wide-angle end, fw represents a focal length of the entire zoom lens at the wide-angle end, and f N  represents a focal length of the N-th lens unit. 
 
     
     
       2. A zoom lens according to  claim 1 , wherein, at a telephoto end compared with at the wide-angle end, the distance between the (N−2)-th lens unit and the (N−1)-th lens unit is longer, and the distance between the (N−1)-th lens unit and the N-th lens unit is shorter. 
     
     
       3. A zoom lens according to  claim 1 , wherein the following condition is satisfied:
   0.20 <|f   N-2   /f   N-1 |<0.70 
 
       where f N-2  represents a focal length of the (N−2)-th lens unit, and f N-1  represents a focal length of the (N−1)-th lens unit. 
     
     
       4. A zoom lens according to  claim 1 , wherein the entire (N−1)-th lens unit constitutes the image stabilizing unit. 
     
     
       5. A zoom lens according to  claim 1 , wherein the N-th lens unit is constituted by one lens having an aspheric lens surface. 
     
     
       6. A zoom lens according to  claim 1 , wherein the following condition is satisfied:
   0.30 <Hd/TDw< 0.70 
 
       where Hd represents a distance between a rear principal point of the (N−2)-th lens unit and an image plane at the wide-angle end. 
     
     
       7. A zoom lens according to  claim 1 , wherein the (N−2)-th lens unit and the N-th lens unit are moved along a same movement locus during the zooming. 
     
     
       8. A zoom lens according to  claim 1 , wherein the zoom lens comprises in order from the object side to the image side:
 the first lens unit; 
 the second lens unit; 
 a third lens unit having a positive refractive power; 
 a fourth lens unit having a negative refractive power; 
 a fifth lens unit having a positive refractive power; 
 a sixth lens unit having a negative refractive power; and 
 a seventh lens unit having a positive refractive power, 
 wherein the first to seventh lens units are each moved in the direction of the optical axis during the zooming. 
 
     
     
       9. A zoom lens according to  claim 1 , wherein the zoom lens comprises in order from the object side to the image side:
 the first lens unit; 
 the second lens unit; 
 a third lens unit having a positive refractive power; 
 a fourth lens unit having a negative refractive power; and 
 a fifth lens unit having a positive refractive power, 
 wherein the first to fifth lens units are each moved in the direction of the optical axis during the zooming. 
 
     
     
       10. An image pickup apparatus comprising:
 a zoom lens; and 
 an image sensor to receive an optical image formed by the zoom lens, 
 wherein the zoom lens comprises in order from an object side to an image side where N represents an integer equal to 5 or 7:
 a first lens unit having a positive refractive power; 
 a second lens unit having a negative refractive power; 
 an (N−2)-th lens unit having a positive refractive power; 
 an (N−1)-th lens unit having a negative refractive power; and 
 an N-th lens unit having a positive refractive power, 
 wherein distances between adjacent ones of the first, second, (N−2)-th, (N−1)-th and N-th lens units in a direction of an optical axis are changed during zooming, 
 wherein the (N−1)-th lens unit includes an image stabilizing unit movable for image blur correction in a direction including a directional component orthogonal to the optical axis, and 
 wherein the following conditions are satisfied:
   0.01 <BldN/TDw< 0.09 
   2.0 <f   N   /fw< 8.0 
 
 
 where BldN represents a thickness of the N-th lens unit on the optical axis, TDw represents a distance on the optical axis between a most object side lens surface and a most-image side lens surface at a wide-angle end, fw represents a focal length of the entire zoom lens at the wide-angle end, and f N  represents a focal length of the N-th lens unit.